20 THE BORDERLAND OF SCIENCE. 



of our galaxy, and forming, therefore, part and parcel 

 of its constitution. Nay, more ; he stated his belief, 

 and brought strong evidence to show, that this vaporous 

 matter was the substance out of which the stars have 

 been made. He pointed to different milky nebulas 

 which seemed to belong to different stages of growth, 

 from an exceedingly faint and altogether irregular 

 nebulosity, to rounded nebulae, nebulae with faint 

 centres, nebulae with bright centres, nebulae consisting 

 almost wholly of a bright central light (the outer por- 

 tion being scarcely discernible), and, finally, nebulous 

 stars this being the last recognizable stage in the 

 progress to actual stars or suns.* 



There is something singularly impressive in the ideas 

 suggested by this theory, whether as respects extension 

 in space or duration of time. Of course, in one re- 

 spect, this new view of certain orders of nebulae implied 

 an enormous diminution of the estimated dimensions 

 of these objects. Taking, for instance, the wonderful 

 mass of nebulous light which seems to cling around 

 the sword of the giant Orion, it will be obvious that if 

 this object were supposed to lie far beyond the limits 

 of our star-system, and to consist of countless millions 

 of suns so far off as not to be separately discernible, 

 the nebula would be an altogether more wonderful 

 object than it becomes on the supposition that it lies 

 within our galaxy, or even nearer (as Sir W. Herschel 



* I purposely omit here any reference to Sir William Herschel's 

 explanation of the so-called planetary nebulae ; because neither the ex- 

 planation itself nor the objections to it would well admit of popular 

 exposition, at least within the space here at my disposal. 



